1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
|
/*
* Simple FTP transparent proxy for in-kernel use. For use with the NAT
* code.
*/
#if SOLARIS && defined(_KERNEL)
extern kmutex_t ipf_rw;
#endif
#define isdigit(x) ((x) >= '0' && (x) <= '9')
#define IPF_FTP_PROXY
#define IPF_MINPORTLEN 18
#define IPF_MAXPORTLEN 30
#define IPF_MIN227LEN 39
#define IPF_MAX227LEN 51
int ippr_ftp_init __P((void));
int ippr_ftp_out __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
int ippr_ftp_in __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
int ippr_ftp_portmsg __P((fr_info_t *, ip_t *, nat_t *));
int ippr_ftp_pasvmsg __P((fr_info_t *, ip_t *, nat_t *));
u_short ipf_ftp_atoi __P((char **));
static frentry_t natfr;
/*
* Initialize local structures.
*/
int ippr_ftp_init()
{
bzero((char *)&natfr, sizeof(natfr));
natfr.fr_ref = 1;
natfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
return 0;
}
/*
* ipf_ftp_atoi - implement a version of atoi which processes numbers in
* pairs separated by commas (which are expected to be in the range 0 - 255),
* returning a 16 bit number combining either side of the , as the MSB and
* LSB.
*/
u_short ipf_ftp_atoi(ptr)
char **ptr;
{
register char *s = *ptr, c;
register u_char i = 0, j = 0;
while ((c = *s++) && isdigit(c)) {
i *= 10;
i += c - '0';
}
if (c != ',') {
*ptr = NULL;
return 0;
}
while ((c = *s++) && isdigit(c)) {
j *= 10;
j += c - '0';
}
*ptr = s;
return (i << 8) | j;
}
int ippr_ftp_portmsg(fin, ip, nat)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
{
char portbuf[IPF_MAXPORTLEN + 1], newbuf[IPF_MAXPORTLEN + 1], *s;
tcphdr_t *tcp, tcph, *tcp2 = &tcph;
size_t nlen = 0, dlen, olen;
u_short a5, a6, sp, dp;
u_int a1, a2, a3, a4;
struct in_addr swip;
int off, inc = 0;
fr_info_t fi;
nat_t *ipn;
mb_t *m;
#if SOLARIS
mb_t *m1;
#endif
tcp = (tcphdr_t *)fin->fin_dp;
bzero(portbuf, sizeof(portbuf));
off = (ip->ip_hl << 2) + (tcp->th_off << 2);
#if SOLARIS
m = fin->fin_qfm;
dlen = msgdsize(m) - off;
if (dlen > 0)
copyout_mblk(m, off, MIN(sizeof(portbuf), dlen), portbuf);
#else
m = *(mb_t **)fin->fin_mp;
dlen = mbufchainlen(m) - off;
if (dlen > 0)
m_copydata(m, off, MIN(sizeof(portbuf), dlen), portbuf);
#endif
if (dlen == 0)
return 0;
portbuf[sizeof(portbuf) - 1] = '\0';
*newbuf = '\0';
if (!strncmp(portbuf, "PORT ", 5)) {
if (dlen < IPF_MINPORTLEN)
return 0;
} else
return 0;
/*
* Skip the PORT command + space
*/
s = portbuf + 5;
/*
* Pick out the address components, two at a time.
*/
a1 = ipf_ftp_atoi(&s);
if (!s)
return 0;
a2 = ipf_ftp_atoi(&s);
if (!s)
return 0;
/*
* check that IP address in the PORT/PASV reply is the same as the
* sender of the command - prevents using PORT for port scanning.
*/
a1 <<= 16;
a1 |= a2;
if (a1 != ntohl(nat->nat_inip.s_addr))
return 0;
a5 = ipf_ftp_atoi(&s);
if (!s)
return 0;
if (*s == ')')
s++;
/*
* check for CR-LF at the end.
*/
if (*s == '\n')
s--;
if ((*s == '\r') && (*(s + 1) == '\n')) {
s += 2;
a6 = a5 & 0xff;
} else
return 0;
a5 >>= 8;
/*
* Calculate new address parts for PORT command
*/
a1 = ntohl(ip->ip_src.s_addr);
a2 = (a1 >> 16) & 0xff;
a3 = (a1 >> 8) & 0xff;
a4 = a1 & 0xff;
a1 >>= 24;
olen = s - portbuf;
(void) sprintf(newbuf, "%s %u,%u,%u,%u,%u,%u\r\n",
"PORT", a1, a2, a3, a4, a5, a6);
nlen = strlen(newbuf);
inc = nlen - olen;
#if SOLARIS
for (m1 = m; m1->b_cont; m1 = m1->b_cont)
;
if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
mblk_t *nm;
/* alloc enough to keep same trailer space for lower driver */
nm = allocb(nlen, BPRI_MED);
PANIC((!nm),("ippr_ftp_out: allocb failed"));
nm->b_band = m1->b_band;
nm->b_wptr += nlen;
m1->b_wptr -= olen;
PANIC((m1->b_wptr < m1->b_rptr),
("ippr_ftp_out: cannot handle fragmented data block"));
linkb(m1, nm);
} else {
if (m1->b_datap->db_struiolim == m1->b_wptr)
m1->b_datap->db_struiolim += inc;
m1->b_datap->db_struioflag &= ~STRUIO_IP;
m1->b_wptr += inc;
}
copyin_mblk(m, off, nlen, newbuf);
#else
if (inc < 0)
m_adj(m, inc);
/* the mbuf chain will be extended if necessary by m_copyback() */
m_copyback(m, off, nlen, newbuf);
#endif
if (inc != 0) {
#if SOLARIS || defined(__sgi)
register u_32_t sum1, sum2;
sum1 = ip->ip_len;
sum2 = ip->ip_len + inc;
/* Because ~1 == -2, We really need ~1 == -1 */
if (sum1 > sum2)
sum2--;
sum2 -= sum1;
sum2 = (sum2 & 0xffff) + (sum2 >> 16);
fix_outcksum(&ip->ip_sum, sum2, 0);
#endif
ip->ip_len += inc;
}
/*
* Add skeleton NAT entry for connection which will come back the
* other way.
*/
sp = htons(a5 << 8 | a6);
/*
* The server may not make the connection back from port 20, but
* it is the most likely so use it here to check for a conflicting
* mapping.
*/
dp = htons(fin->fin_data[1] - 1);
ipn = nat_outlookup(fin->fin_ifp, IPN_TCP, nat->nat_p, nat->nat_inip,
ip->ip_dst, (dp << 16) | sp);
if (ipn == NULL) {
bcopy((char *)fin, (char *)&fi, sizeof(fi));
bzero((char *)tcp2, sizeof(*tcp2));
tcp2->th_win = htons(8192);
tcp2->th_sport = sp;
tcp2->th_dport = 0; /* XXX - don't specify remote port */
fi.fin_data[0] = ntohs(sp);
fi.fin_data[1] = 0;
fi.fin_dp = (char *)tcp2;
swip = ip->ip_src;
ip->ip_src = nat->nat_inip;
ipn = nat_new(nat->nat_ptr, ip, &fi, IPN_TCP|FI_W_DPORT,
NAT_OUTBOUND);
if (ipn != NULL) {
ipn->nat_age = fr_defnatage;
(void) fr_addstate(ip, &fi, FI_W_DPORT);
}
ip->ip_src = swip;
}
return inc;
}
int ippr_ftp_out(fin, ip, aps, nat)
fr_info_t *fin;
ip_t *ip;
ap_session_t *aps;
nat_t *nat;
{
return ippr_ftp_portmsg(fin, ip, nat);
}
int ippr_ftp_pasvmsg(fin, ip, nat)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
{
char portbuf[IPF_MAX227LEN + 1], newbuf[IPF_MAX227LEN + 1], *s;
int off, olen, dlen, nlen = 0, inc = 0;
tcphdr_t tcph, *tcp2 = &tcph;
struct in_addr swip, swip2;
u_short a5, a6, dp, sp;
u_int a1, a2, a3, a4;
tcphdr_t *tcp;
fr_info_t fi;
nat_t *ipn;
mb_t *m;
#if SOLARIS
mb_t *m1;
#endif
tcp = (tcphdr_t *)fin->fin_dp;
off = (ip->ip_hl << 2) + (tcp->th_off << 2);
m = *(mb_t **)fin->fin_mp;
bzero(portbuf, sizeof(portbuf));
#if SOLARIS
m = fin->fin_qfm;
dlen = msgdsize(m) - off;
if (dlen > 0)
copyout_mblk(m, off, MIN(sizeof(portbuf), dlen), portbuf);
#else
dlen = mbufchainlen(m) - off;
if (dlen > 0)
m_copydata(m, off, MIN(sizeof(portbuf), dlen), portbuf);
#endif
if (dlen == 0)
return 0;
portbuf[sizeof(portbuf) - 1] = '\0';
*newbuf = '\0';
if (!strncmp(portbuf, "227 ", 4)) {
if (dlen < IPF_MIN227LEN)
return 0;
else if (strncmp(portbuf, "227 Entering Passive Mode", 25))
return 0;
} else
return 0;
/*
* Skip the PORT command + space
*/
s = portbuf + 25;
while (*s && !isdigit(*s))
s++;
/*
* Pick out the address components, two at a time.
*/
a1 = ipf_ftp_atoi(&s);
if (!s)
return 0;
a2 = ipf_ftp_atoi(&s);
if (!s)
return 0;
/*
* check that IP address in the PORT/PASV reply is the same as the
* sender of the command - prevents using PORT for port scanning.
*/
a1 <<= 16;
a1 |= a2;
if (a1 != ntohl(nat->nat_oip.s_addr))
return 0;
a5 = ipf_ftp_atoi(&s);
if (!s)
return 0;
if (*s == ')')
s++;
if (*s == '\n')
s--;
/*
* check for CR-LF at the end.
*/
if ((*s == '\r') && (*(s + 1) == '\n')) {
s += 2;
a6 = a5 & 0xff;
} else
return 0;
a5 >>= 8;
/*
* Calculate new address parts for 227 reply
*/
a1 = ntohl(ip->ip_src.s_addr);
a2 = (a1 >> 16) & 0xff;
a3 = (a1 >> 8) & 0xff;
a4 = a1 & 0xff;
a1 >>= 24;
olen = s - portbuf;
(void) sprintf(newbuf, "%s %u,%u,%u,%u,%u,%u\r\n",
"227 Entering Passive Mode", a1, a2, a3, a4, a5, a6);
nlen = strlen(newbuf);
inc = nlen - olen;
#if SOLARIS
for (m1 = m; m1->b_cont; m1 = m1->b_cont)
;
if ((inc > 0) && (m1->b_datap->db_lim - m1->b_wptr < inc)) {
mblk_t *nm;
/* alloc enough to keep same trailer space for lower driver */
nm = allocb(nlen, BPRI_MED);
PANIC((!nm),("ippr_ftp_out: allocb failed"));
nm->b_band = m1->b_band;
nm->b_wptr += nlen;
m1->b_wptr -= olen;
PANIC((m1->b_wptr < m1->b_rptr),
("ippr_ftp_out: cannot handle fragmented data block"));
linkb(m1, nm);
} else {
m1->b_wptr += inc;
}
copyin_mblk(m, off, nlen, newbuf);
#else
if (inc < 0)
m_adj(m, inc);
/* the mbuf chain will be extended if necessary by m_copyback() */
m_copyback(m, off, nlen, newbuf);
#endif
if (inc != 0) {
#if SOLARIS || defined(__sgi)
register u_32_t sum1, sum2;
sum1 = ip->ip_len;
sum2 = ip->ip_len + inc;
/* Because ~1 == -2, We really need ~1 == -1 */
if (sum1 > sum2)
sum2--;
sum2 -= sum1;
sum2 = (sum2 & 0xffff) + (sum2 >> 16);
fix_outcksum(&ip->ip_sum, sum2, 0);
#endif
ip->ip_len += inc;
}
/*
* Add skeleton NAT entry for connection which will come back the
* other way.
*/
sp = 0;
dp = htons(fin->fin_data[1] - 1);
ipn = nat_outlookup(fin->fin_ifp, IPN_TCP, nat->nat_p, nat->nat_inip,
ip->ip_dst, (dp << 16) | sp);
if (ipn == NULL) {
bcopy((char *)fin, (char *)&fi, sizeof(fi));
bzero((char *)tcp2, sizeof(*tcp2));
tcp2->th_win = htons(8192);
tcp2->th_sport = 0; /* XXX - fake it for nat_new */
fi.fin_data[0] = a5 << 8 | a6;
tcp2->th_dport = htons(fi.fin_data[0]);
fi.fin_data[1] = 0;
fi.fin_dp = (char *)tcp2;
swip = ip->ip_src;
swip2 = ip->ip_dst;
ip->ip_dst = ip->ip_src;
ip->ip_src = nat->nat_inip;
ipn = nat_new(nat->nat_ptr, ip, &fi, IPN_TCP|FI_W_SPORT,
NAT_OUTBOUND);
if (ipn != NULL) {
ipn->nat_age = fr_defnatage;
(void) fr_addstate(ip, &fi, FI_W_SPORT);
}
ip->ip_src = swip;
ip->ip_dst = swip2;
}
return inc;
}
int ippr_ftp_in(fin, ip, aps, nat)
fr_info_t *fin;
ip_t *ip;
ap_session_t *aps;
nat_t *nat;
{
return ippr_ftp_pasvmsg(fin, ip, nat);
}
|